1. Field of the Invention
This invention relates to the field of circulation systems for bodies of water and more particularly to such circulation systems for relatively small and shallow bodies of water such as a small pond as well as relatively small portions of larger bodies of water such as at boat marinas and lake coves.
2. Discussion of the Background
Relatively small and shallow bodies of water often experience water quality issues related to the lack of thorough circulation. For many such bodies, water movement caused by wind, water currents, water run off, and other natural occurrences are simply not adequate enough to beneficially circulate the water.
Poor water quality of such bodies can significantly reduce the property values for those who own or live near the surrounding land; however, more importantly, it can lead to health problems for those who use the water body for work or recreation as well as animals that rely on it. Many human and animal health concerns have been traced to a number of water quality issues such as harmful algae blooms, invasive weeds, and low dissolved oxygen levels. For water bodies that are lacking thorough circulation from natural causes, additional circulation is needed to reduce and in many cases eliminate a stagnate water situation which can dramatically contribute to poor and unhealthy water quality.
A number of prior mixing and aeration systems have operated under the principle of rapid, turbulent flow patterns. However, it has been observed that this type of mixing has a relatively small zone of circulation influence around the mixer or aerator. Consequently, to achieve a thorough circulation of the entire water body with this approach, the mixer or aerator must be relatively large with high power requirements or there must be a relatively large number of such machines to do the job. Observations have suggested that a preferred approach to such turbulent machines is to provide a circulator that can create a nearly laminar, surface flow pattern out to the edges of the water body while drawing up water from the depths of the body. Economic and safety considerations generally dictate that such nearly laminar flow circulators have low voltage and power requirements while esthetic considerations in certain situations (e.g., residential or golf course ponds) dictate that the circulator preferably be completely submersible to be out of view.
In these regards, a circulation system operating on a relatively low voltage and power demand poses less risk of electrocution or injury to owners, residents, and users of the water body as well as to any animals that rely on it. Additionally, for a water body such as a residential or golf course pond, a completely submerged circulator is desirable to give the pond a pristine, natural look. The submerged circulator including its components and operation are then preferably undetectable even at close distances; however, the submersible circulator must still be capable of thoroughly circulating the deep water as well as the surface water. Without circulation of the surface water, a thin film or cover becomes established and blocks exposure to the oxygen rich atmosphere and the effectiveness of circulating the water is greatly diminished. Previous devices in this field of circulating systems have addressed this surface renewal issue but have had to do so using a floating platform and dish. The platform and flotation for it are above the waterline and where it is desired that no part of the circulator be visible to destroy the natural setting of the water, these floating systems are unacceptable.
An additional benefit of having a submersible system in contrast to one that has components above the surface is that harmful and noticeable fouling by birds or other animals is prevented. Less maintenance is then required to keep the circulator working and the pond or other body of water looking pristine. Also, vandals are less likely to notice a submerged circulation system and damage or steal it.
Thus, in a well-designed system for relatively small and shallow bodies of water as indicated above, the surface of the pond or other body of water would be continually renewed with water drawn up from the bottom depths. Further, this would be done while maintaining a substantially laminar surface flow out to the edges of the pond. The surface water would then absorb oxygen from the atmosphere while undesirable gases such as hydrogen sulfide would pass out of the water into the atmosphere. The circulator would also preferably have relatively low voltage and power requirements and be completely submersible to be totally out of view.
With these and other desirable characteristics in mind, the submersible circulation system of the present invention was developed. With it, a nearly laminar surface flow out to the edges of the water body is created while uplifting water from the bottom or lower depths of the pond for treatment. In doing so, the oxygen depleted water from the bottom depths is exposed to the atmosphere to absorb oxygen from it and undesirable gases such as hydrogen sulfide are passed off into the atmosphere. Additionally, the current invention generates an overall circulation pattern that mixes the re-aerated water throughout the body of water to aid and accelerate the biological and solar processes that clean up the water. The resulting cleansing is particularly effective in controlling or removing weed growth, algae blooms, sludge buildup, fish kills, odors, high amounts of nitrogen and phosphorous, acidity, suspended solids, and other undesirable conditions. In a modified embodiment, a small surface float is used with the system while still maintaining and achieving the desired circulation benefits discussed above.